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<title>gl.texImage2D() test to Wasm Memory 4GB in size.</title>
<link rel="stylesheet" href="../../resources/js-test-style.css"/>
<script src="../../js/js-test-pre.js"></script>
<script src="../../js/webgl-test-utils.js"> </script>
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<script>
"use strict";
description(document.title);
debug("Tests that texImage2D can be called on the end of a ~2GB view into ~4GB of WebAssembly Memory.");
debug("");
let wtu = WebGLTestUtils;
let gl = wtu.create3DContext("canvas", undefined, 2);

const PAGE = 65536;
const HEAP_SIZE = 4 * 1024 * 1024 * 1024 - PAGE;
const VIEW_SIZE = 2 * 1024 * 1024 * 1024 - PAGE;
(() => {
  let view;
  try {
    view = new Uint8Array(new WebAssembly.Memory({ initial: HEAP_SIZE / PAGE }).buffer, 0, VIEW_SIZE);
  } catch (e) {
    testPassed(`Allocating ${HEAP_SIZE} threw: ${e}`);
    return;
  }


  function compileShader(type, src) {
    let shader = gl.createShader(type);
    gl.shaderSource(shader, src);
    gl.compileShader(shader);
    let log = gl.getShaderInfoLog(shader);
    if (log) debug(log);
    return shader;
  }

  function createProgram(vs, fs) {
    let program = gl.createProgram();
    gl.attachShader(program, vs);
    gl.attachShader(program, fs);
    gl.bindAttribLocation(program, 0, 'pos');
    gl.linkProgram(program);
    gl.useProgram(program);
    return program;
  }

  let program = createProgram(
    compileShader(gl.VERTEX_SHADER, `
      varying vec2 uv;
      attribute vec2 pos;
      void main() { uv = pos; gl_Position = vec4(pos*2.0-vec2(1.0,1.0),0,1); }`),
    compileShader(gl.FRAGMENT_SHADER, `
      precision lowp float;
      uniform sampler2D tex;
      varying vec2 uv;
      void main() { gl_FragColor = texture2D(tex,uv); }`));

  gl.bindBuffer(gl.ARRAY_BUFFER, gl.createBuffer());
  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([0, 0, 1, 0, 0, 1, 1, 1]), gl.STATIC_DRAW);
  gl.vertexAttribPointer(0, 2, gl.FLOAT, gl.FALSE, 0, 0);
  gl.enableVertexAttribArray(0);

  let texture = gl.createTexture();
  gl.bindTexture(gl.TEXTURE_2D, texture);

  // Test uploading an image
  const expectedColor = [42, 84, 128, 255];
  const offset = view.length - expectedColor.length;
  view.set(expectedColor, offset);
  try {
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, view, offset);
  } catch (e) {
    testFailed(`texImage2D from ${view.length} byte view threw: ${e}`);
    return;
  }
  wtu.glErrorShouldBe(gl, gl.NO_ERROR);

  // Test rendering with that image
  gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);

  // Verify that we rendered what we expected
  wtu.checkCanvasRect(gl, 0, 0, 1, 1, expectedColor, "texImage2D produced expected color");
})();

var successfullyParsed = true;
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